This invention relates to a nozzle for depositing a layer of fluid mass, more particularly foamed dough.
There are various types of extrusion nozzles comprising one or more extrusion slots for forming one or more strips of dough intended, in particular, for the production of flat loaves or pizza bases, for example.
The problems involved in the design of these known nozzles concern the need to obtain strips having a uniform thickness or smooth surface which can be cut into articles of regular shape. These problems have been solved in particular as a function of the fact that the dough to be extruded to make flat loaves or pizza bases has a relatively firm plastic consistency and that fairly considerable pressure has to be applied to the dough to force it through the slots.
Thus, in one known nozzle, a grid or diffusion passages opening into a pressure equalizing chamber are provided between the head of the screws of an extruder and the extrusion slots.
Similarly, in another known nozzle, the extrusion slot is preceded by a diaphragm itself comprising a slot which is narrower at the center than at the sides, for example, so as to establish a certain uniformity of the stream of dough which moved at a higher speed at its center than at its sides.
However, these known solutions are hardly applicable to the deposition of a layer of fluid mass, particularly expanded dough, for example "Genoese" dough.
The deposition of a layer of fluid mass onto a conveyor belt intended, for example, to transport the mass through a treatment installation, such as an oven or cooking tunnel for example, can involve difficulties similar to those mentioned above. This is because it may be necessary to obtain a layer having a uniform thickness and texture and a regular surface over its entire width. However, this is more difficult, the wider the layer. Now, in continuous industrial production, for example, it is essential to be able continuously to deposit a layer of fluid mass as wide as possible in order fully to exploit the capacity of a treatment installation of large dimensions.
The problem addressed by the present invention is to provide a nozzle which enables this industrial objective to be optimally achieved.